Electrode



July 27, 1948. E. F. LOWRY ET AL 2,446,157

ELECTRODE Filed May 23, 1946 mrmiiz 3311mm Arnold itqflmcnck imam fluZfqslmn INVENTORS' ATTORN EY Patented July 27, 1948 UNITED STATESPATENT. OFFICE mac'mona Erwin r. Lowry. Lynn, Arnold 1.. re ime. Dan-.vers, and William E. Leyshon, Salem, Mass, asfl ora to SylvaniaElectric .Products Inc" Salem. Mala, a corporation of MassachusettsApplication May 23, 1946, Serial No. 671,688

reclaims. 1

This invention relates to electric gaseous discharge devices and moreparticularly to those of the negative glowtype.

An o ject of this invention is to'provide an electrode for a negativeglow discharge lamp.

Another-object of this invention is -to provide an electrode which willpermit'maximum lightoutput.

. A further object is .to provide an electrode which will permit thelamp to be started at relatively low voltages.-

Another'object is to provide an electrode which is especially adaptedfor use in a glass envelope or other suitable container which isrelatively small-in size.

Another object is to provide an electrode which possible the completeand substantially uniform illumination of the entire surface of theenvelope in which the electrode is sealed.

Further objects, advantages and features will be. apparent from thefollowing specification when read in conjunction with the accompanyingdrawing in which:

Figure 1 shows a lamp provided with the electrode assembly of ourinvention.

is so constructed geometrically that it makes stantially. frusto-conicalin contour and the projected apex of the cone falls within the bulb.

no part of the bulb wall is hidden from the radiation originating at thesurface of the electrode assembly.

Our invention is further characterized by a novel positioning of thiselectrode structure with reference to the stem'on which it is mounted.We have found that when this particular type of electrode structure isemployed it permits the lower portion of the frusto-conical electrodestructure to be fitted over the upper portion of the stem. This is afeature which is particularly bulb wall than others, thus causing a morecon- Figure 2 is a front elevational view of a lamp mount with theelectrode assembly of our invention mounted thereon.

Figure 3 is-a partial sectional view taken along v the longitudinal axisof the mount of Figure 2.

Our invention embodies the idea of providing a glow lamp with a new andnovel electrode structure and assembly which comprises two identicalstamped metal members which serve as the electrodes and which, whendisposed on a suitable stem, present a substantially frustoconical"structure with the longitudinal peripheral edges of the two membersadjacent each other and spaced a short distance apart, and the The outercentrated radiation at these points. These concentrated points ofradiation are not present in our structure.

Another advantage which is "obtained by the frustoconical electrodestructure of our invention is that it makes it considerably easier toapply a uniform coating of electron-emissive material thereto becausethe surface thereof is substantially a surface of revolution. is anadded factor which contributes to the attainment of a light source whichgives uniform light distribution.

The above-described structural features makes "practical the use of astem with a long throat.

This in turn permits the disposition of a ballastfun'ctions alternatelyas the cathode and then the anode. Since the electrode assembly issubing resistor within the-throat as an integral part of one of the leadwires; This is a distinct advantage over conventional structures whichusually incorporate the resistor in the lamp base.

Referring now to the drawing, the electrode assembly I, comprisingelectrode members 2 and 3, are supported by the wires 4' and 5 which aresealed in the press 6 of a stem I. The stem 1 is and 3 of the electrodeassembly I. The elongated throat 8 of the stem 1 provides a suitablechamber for a ballasting resistor 13 which forms a part of one of thelead wires. The stem press 6 is provided with an aperture l4 and atubulatlon l through which a connection may be made to any suitablesystem adapted to evacuate the bulb Hljafter the stem 1 has been scaledthereto.

The electrode members 2 and 3, when mounted on the wires 4 and 5,present a substantially frusto-conical structure with the longitudinalperipheral edges 1'6 adjacent each other and spacedpermits theillumination of the entire bulb surface with no part of the bulb wallhidden from radiation originating at the surface of the electrodeassembly, without using a continuous electrode surface such as isproduced by expensive deep-drawing operations. The conical design alsoallows the electrode assembly to be fitted around the top portion ofthe/stem, thus economizing on a short distance apart. Each electrodemember 2 and 3 is provided with a. channel i8 which defines wings 25extending longitudinally thereof, in which the upper portions of thewires 4 and 5 are seated. The wings 25 are crimped and the wires 4 and 5are spot welded to the crimped wings at 26. The seating of a largeportion of the wires 4 and 5 in these channels permits spot welding ofthe wires to the crimped wings at only one point without impairing therigidity of the structure. The electrode members 2 and 3 may be providedwith a circumferential rib 29 disposed adjacent the base of theelectrode assembly structure. The rib 29 serves to reinforce thestructure. This structural arrangement is particularly advantageous inthe present application where a relatively small bulb I0 is used becauseit permits a more compact and sturdier mount assembly.

Another feature of the electrode assembly I, which is particularlyadvantageous for the reasons above-mentioned when a small bulb is usedis embodied in the disposition of the assembly I with respect to thestem I. The lower edges II which form the base of the frusto-conicalelectrode assembly i extend down over the upper portion of the stem.This is an additional structural feature which characterizes thecompact, sturdy electrode structure of our invention.

It has been the practice, whenever it was desired to incorporate aballasting resistor in an electronic device to place it withinthe mainbody thereof and shielded from the discharge or in the base. When adevice as small as the one shown and described in this application isconcerned, neither of these two conventional methods proved verysatisfactory. Therefore we have provided the stem 1 with an elongatedthroat 8, the walls thereof defining a suitable chamber within which aballasting resistor I3 may be disposed, Thus the composite lead wire I2comprises the wire Hi the resistor l3 and the wire H! which is connectedthrough the stem press 6 to the electrode-supporting wire 5.

The mount which comprises the stem and electrode assemblies is sealed ina glass bulb ill, the inner wall of which is provided with a coating offluorescent material H. The outer surface of the electrodes 2 and 3 isprovided with a suitable coating 22 Of an oxide of one or more of thealkaline earth metals, such as barium peroxide for example. The innersurface of the electrodes 2 and 3 may be provided with a suitablecoating 23 of zirconium or titanium metal powder to act as a getterduring evacuation of the lamp 24 and to prevent emission from the innersurfaces of the electrodes 2 and 3 during operation of the lamp.

The conical design of the electrode assembly I is particularly adaptedto the fluorescent type glow lamp. The projected apex of the completecone surface, of which the frustum is a part is designed to fall withinthe bulb dimensions. This mount space and permitting a stem with anelongated throat to be used. The long-throated stem makes a sturdiermount and provides a suitable chamber for a resistor as part of one ofthe lead wires. I

What we claim is:

1. A mount assembly for an electric gaseous discharge devicecomprising astem, 9. pair of electrode-supporting wires sealed in and projectingfrom said stem, and a pair of electrodes mounted on said wires, saidelectrodes defining a substantially frusto-conical structure, thelongitudinal peripheral edges of the electrodes being adjacent eachother and spaced a short distance apart.

2. A mount assembly for an electric gaseous discharge device comprisinga stem, a pair of electrode-supporting wires sealed in and projectingfrom said stem, and a pair of electrodes mounted on said wires, saidelectrodes defining a substantially frusto-conical structure, thelongitudinal peripheral edges of the electrodes being adjacent eachother and spaced a short distance apart and the peripheral edges whichdefine the base of said frusto-conical structure being disposedsubstantially below the top of said stem.

3. A mount assembly for an electric gaseous discharge device comprising'a stem having a press and an elongated throat, a pair ofelectrode-supporting wires sealed in and projecting from said press, anda pair of electrodes mounted on said wires, said electrodes defining asubstantially frusto-conical structure, the longitudinal peripheraledges of the electrodes being adjacent each other and spaced a shortdistance apart.

4. A mount assembly for an electric gaseous discharge device comprisinga stem having a' press and an elongated throat a pair ofelectrode-"supporting wires sealed in, and projecting from said press,and a pair of electrodes mounted on said wires, said electrodes defininga substantially frusto-conical structure, the longitudinal peripheraledges of the electrodes being adjacent each other and spaced a shortdistance apart, and the peripheral edges which define the base of saidfrusto-conical structure bein disposed substantially below the top ofsaid stem.

5. A mount assembly for an electric gaseous discharge device comprisinga stem having a press and an elongated throat, a pair ofelectrodesupporting wires sealed in and projecting from said press, apair of electrodes mounted on said wires, said electrodes defining asubstantially frusto-conical structure, the longitudinal peripheraledges of the electrode being adjacent each other and spaced a shortdistance apart, a pair of lead wires connected through the stem press tosaid electrode-supporting wires and extending through a chamber definedby said elongated throat, and a resistor connected to one of said leadwires and disposed within the chamber defined by the elongated throat ofthe stem.

6. A mount assembly for an electric gaseous discharge device comprisinga stem having a press and an elongated throat, a pair ofelectrodesupporting wires sealed in and projecting from said press, apair of electrodes mounted on said wires, said electrodes defining asubstantially i a chamber defined by said elongated throat, and

a resistor connected to one of said lead wires and disposed within thechamber defined by the elongated throat of the stem.

7. An electric gaseous discharge device comprising a glass envelope, astem sealed in said envelope, a pair of electrode-supporting wiressealed in and projecting upwardly from said stem into the chamberdefined by said glass envelope and a pair of electrodes mounted on saidwires, said electrodes defining a substantially frusto-conical structurein which the longitudinal peripheral edges of the electrodes areadjacent each other and spaced a short distance apart, and the projectedapex of the cone-like structure falls within the chamber defined by theglass envelope.

8. An electric gaseous discharge device comprising a glass envelope, astem sealed in said envelope, a pair of electrode-supporting wiressealed in and projecting upwardly from said stem into the chamberdefined by said glass envelope, and a pair of electrodes mounted on saidwires, said electrodes defining a substantially frustoconical structurein which the longitudinal peripheral edges of the electrodes areadjacent each other and spaced a short distance apart, the peripheraledges which define the base of said frusto-conical structure aredisposed substantially below the top of said stem, and the projectedapex of the cone-like structure falls within the chamber defined by theglass envelope.

9. An electric gaseous discharge device comprising a glass envelope, afillingof an inert gas in said envelope, a coating of luminescent material on the inner wall of said envelope, a stem sealed in said envelope,a pair of electrode-supporting wires sealed in and projecting upwardlyfrom said stem into the chamber defined by said glass envelope and apair of electrodes mounted .tudinal peripheral edges of the electrodesare adjacent each other and spaced a short distance apart, theperipheral edges which define the base stantially below the top of saidstem, and the" projected apex of the cone-like structure falls withinthe chamber defined by the glass envelope.

11. An electric gaseous discharge device comprising a glass envelope, afilling of an inert gas in said envelope, a coating of luminescentmaterial on the inner wall of said envelope, a stem sealed in saidenvelope, a pair of electrode-supporting wires sealed in and projectingupwardly from said stem into the chamber defined by said glass envelopeand a pair of electrodes mounted on said wires, said electrodes defininga substantially frusto-conical structure in which the longitudinalperipheral edges of the electrodes are adjacent each other and spaced ashort distance apart, and the projected apex of the cone-like structurefalls within the chamber defined by the glass envelope, and a coating ofelectron-emissive material on said electrodes.

12. An electric gaseous discharge device comprising a glass envelope, afilling of an inert gas in said envelope, a coating of luminescentmaterial on the inner wall of said envelope, a stem sealed in saidenvelope, a pair of electrode-supporting wires sealed .in and projectedupwardly from said stem into the chamber defined by said glass envelope,and a pair of electrodes mounted on said wires, said electrodes defininga substantially frusto-conical structure in which the longitudinalperipheral edges of the electrodes are adjacent each other and spaced ashort distance apart, the peripheral edges which define the base of saidfrusto-conical structure are disposed subon said wires, said electrodesdefining a substantially frusto-conical structure in which thelongitudinal peripheral edges of the electrodes are adjacent each otherand spaced a short distance apart, and the projected apex of thecone-like structure falls within the chamber defined by the glassenvelope.

10. An electric gaseous discharge device comprising a glass envelope, afilling of an inert gas in said envelope, a coating of luminescentmaterial on the inner wall of said envelope, a stem sealed in saidenvelope, a pair of electrode-supporting wires sealed in and projectingupwardly from said stem into the chamber defined by said glass envelope,and a pair of electrodes mounted on said wires, said electrodes defininga substantially frusto-conical structure in which the longistantiallybelow the top of said stem, and the projected apex of the cone-likestructure falls within the chamber defined by the glass envelope, and acoating of electron-emissive material on said electrodes.

ERWIN F. LOWRY. ARNOLD L. PEACOCK. WILLIAM E. LEYSHON.

REFERENCES cr rEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,816,690 Moore July v28, 19311,879,158 Foulke Sept. 2'1, 1932 1,965,586 Foulke-- July 10*, 19342,298,581 Abadie Oct. 13, 1942 2,409,769 Leyshon Oct. 28, 1946 2,413,650Peacock Dec. 31, 1946 FOREIGN PATENTS Number Country Date 411,683 GreatBritain June 14, 1934 819,881 France July 19, 1937

